(1) Field of the Invention
The present invention relates to glyphosate formulations (herbicides) containing glyphosate and a surfactant consisting essentially of a branched alkylamine where the nitrogen atom in the alkylamine is connected to a branched alkyl group and one, two or three chains of alkylene oxide units (e.g., ethylene oxide units and/or propylene oxide units, including copolymers of ethylene oxide and propylene oxide units).
(2) Description of the Related Art
Important concerns on health and environment exist worldwide on the consequences of the application of herbicides and other pesticides for food production.
The need to strongly increase the yields per hectare and the quality a food are important factors influencing the use of pesticides, mainly considering the problems of hunger.
In order to find a compromise between these two opposite factors, the European Commission published directive 91/414, the US Government published FIFRA, and FAO and the World Health Organisation are preparing a Guideline on the Use of Pesticides to be approved by all countries.
The objective is to harmonize the rules on the sales authorization of pesticides.
It is unacceptable that the World Trade Organisation creates a free market, if food originated in some countries is exported to other countries, where the residues of pesticides in the food do not comply with existing rules in the importing countries.
Since glyphosate was patented by the U.S. company Monsanto, alkylamine polyethoxylated (also known as polyethoxylated amines or polyethoxylated alkylamines) as surfactants were included in the first patents. The alkyl group of the alkylamine polyethoxylated surfactants taught in these patents was a linear alkyl group.
The length of the linear alkyl chain was subject to optimising efforts and the use of other surfactants mixed with alkylamine polyethoxylated surfactants was also tried. The use of other families of compounds like alkylphosphonates polyethoxylated, polysiloxanes, sarcosinates, betain polyethoxylates and many other compounds have been patented. (See U.S. Pat. Nos. 5,258,359; 5,658,853; 5,663,117; 5,912,209; and 6,734,141 as well as European Patent No. 1,541,023).
In our U.S. patent application Ser. No. 12/484,212, we presented the new glyphosate formulation containing branched alkylamines polyethoxylated, and described their advantages in comparison to earlier formulations.
In our U.S. patent application Ser. No. 12/541,989, we described herbicides consisting of a glyphosate formulation containing as a surfactant a branched alkylamine where the nitrogen atom is connected to a chain of propylene oxide monomers (i.e., polypropylenoxide) or to a copolymer of ethylene oxide and propylene oxide monomers, and described their advantages in comparison to earlier formulations.
Branched alkyl alcohol polyethoxylated with alkyl chains with less carbon atoms like 10-12 have been earlier used together with the linear alkylamine polyethoxylated in order to reduce the micelle formation and therefore the surface tension. In this way the content of the classical long chain alkylamines polyethoxylated could be reduced.
In the present invention, we are using the branched alkyl groups in the amine polyalkoxylated (e.g., polyethoxylated) itself. Branches in the alkyl chain create steric hindrance to micelle formation. Micelles consisting of surfactant molecules reduce the amount of surfactant available to decrease the surface tension.
Because of miscibility limitations, the content of the branched alcohol polyethoxylated is limited.
We found that a branched alkyl amine, polyethoxylated mixed or not with a branched alkyl alcohol polyethoxylated makes possible a reduction of isopropylamine, which is a co-formulant, and avoids the micelle formation, which is most important. The speed of penetration of the solution in water of the glyphosate formulation through the membranes of the leaves of the weeds is therefore strongly improved, therefore improving the efficacy of the formulation as a herbicide.